Two proteins from Drosophila melanogaster embryonic nuclei which are soluble in both 0.35 M NaCl and 2% trichloroacetic acid have been tentatively identified as the Drosophila equivalents of the mammalian HMG proteins. One of these proteins has been shown by immunofluorescence to be generally distributed over larval salivary gland polytene chromosomes. We plan to make antisera to the other protein and also to determine its distribution on polytene chromosomes by immunofluoresence. Experiments are planned which will determine the fate of these proteins upon digestion of isolated nuclei with either micrococcal nuclease or DNAase 1. Chromatin fractionation by partial precipitation with 0.1M NaC1 or 2mM MgCl2 will be attempted and these methods will be accessed for their suitability as a means for fractionating Drosophila chromatin into active and inactive portions. Affinity chromatography of nucleosomes will also be attempted if a suitable active chromatin specific protein can be identified and purified.